Intel HD Graphics 630, 6-bit color bug for resolutions over 60hz, Windows 10 v1803, latest DCH drivers

[KGian1]

Hello, it seems the last time you've fixed the 6-bit bug ( https://forums.intel.com/s/question/0D50P0000490Tl9SAE/solved-intelr-hd-graphics-630-6bit-color-windows-10-1803?language=en_US ) you didn't do a good job because the problem still exists in another form.

So essentially now any resolution over 60hz reports 6-bit color depth instead of 8-bit colour depth, but there is a chance it could be a report issue as i don't seem to notice a change in colors between them, although it seems black is darker and white is brighter. Need to find a better way to test it though (i'll look around).

In the meantime please have a look in the attached photos.

Kind regards

[Amy_C_Intel1]

Hello KGian1, Thank you for posting on the Intel® Communities. Did you run any recent Windows 10 updates? What is the DCH driver version you installed? Where can you detect the behavior? On your desktop? Or on an app? If possible, provide a video of this situation. Amy C Intel Customer Support Technician Under Contract to Intel Corporation

[KGian1]

I posted clear photos showing the issue if you were to bother to have a look at them instead of copying-pasting a reply you post everywhere. Forward the issue to someone working under the driver development of the graphics team.

Did you run any recent Windows 10 updates? No, running lastest W10 v1083 fully updated

What is the DCH driver version you installed? Look at the photos, it's written over there

Where can you detect the behavior? On your desktop? Or on an app? I've described you and show you in the photos

If possible, provide a video of this situation. There is no need for a video the photos show the issue.

It's clearly shown in the photos, 60hz refresh rate->8-bit color depth, any refresh rate above 60hz (in my photo example 100hz as it is shown) -> 6-bit color depth

[Amy_C_Intel1]

KGian1, We are reviewing this matter and we would like to request more information, please see below: Has it worked before? If so, using which driver? Let us know your laptop brand and model. Provide your https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility-for-Windows- report. Amy C Intel Customer Support Technician Under Contract to Intel Corporation

[KGian1]

Are you a bot or just slow minded? Obviously you again didn't read what i wrote neither bothered to ask an actual engineer about this. Let me give you the solution since you can't do your job properly. Turns out this is normal operation due to the bandwidth limit of the eDP interface and display running 2 lanes (instead of 4 lanes for 4K), which limits it to 240mhz pixel clock. Therefore in order to fit 1080p@100hz refresh rate the bit depth has to be dropped to 6-bit from 8-bit to fit the signal.

[Amy_C_Intel1]

The issue is occurring only with the built-in laptop screen, thus the best thing to do is to report this to the OEM so that they can reproduce the issue and debug it. If it is found to be with the Intel driver the OEM will work with us to get it fixed. Amy C Intel Customer Support Technician Under Contract to Intel Corporation